Epoxy resin composition, and printed circuit board using same

ABSTRACT

According to one embodiment of the present invention, an epoxy resin composition comprises an epoxy compound, a curing agent, and an inorganic filler, wherein the inorganic filler includes alumina (Al 2 O 3 ) and aluminum nitride (AlN).

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application is a U.S. National Stage Application under 35 U.S.C.§371 of PCT Application No. PCT/KR2013/011313, filed Dec. 6, 2013, whichclaims priority to Korean Patent Application No. 10-2012-0144788, filedDec. 12, 2012, whose entire disclosures are hereby incorporated byreference.

TECHNICAL FIELD

The present invention relates to an epoxy resin composition, and moreparticularly, to an epoxy resin composition and a printed circuit boardincluding an insulating layer formed of the epoxy resin composition.

BACKGROUND ART

A printed circuit board includes a circuit pattern formed on aninsulating layer, and thus a variety of electronic parts may be mountedon the printed circuit board.

For example, the electronic parts mounted on the printed circuit boardmay be heating elements. Heat emitted by the heating elements maydegrade the performance of the printed circuit board. With therealization of high integration and higher capacity of electronic parts,there is an increasing concern about heat dissipation problems ofprinted circuit boards.

An epoxy resin composition including an inorganic filler and an epoxyresin of a bisphenol A type, a bisphenol F type, or the like has beenused to obtain an insulating layer having electrical insulatingproperties and also exhibiting excellent thermal conductivity. Also, aboard made of a ceramic material is used as well (Korean UnexaminedPatent Application Publication No. 2011-0027807).

However, such an epoxy resin composition have a problem in that it isdifficult to handle heat emitted by elements due to its insufficientthermal conductivity.

DISCLOSURE Technical Problem

To solve the above problems, one aspect of the present inventionprovides an epoxy resin composition and a printed circuit board usingthe same.

Technical Solution

According to an aspect of the present invention, there is provided anepoxy resin composition which includes an epoxy compound represented bythe following Formula 1, a curing agent, and an inorganic filler,wherein the inorganic filler includes alumina (Al₂O₃) and aluminumnitride (AlN).

In Formula 1, R¹ to R¹⁴ may each independently be selected from thegroup consisting of H, Cl, Br, F, a C₁-C₃ alkyl, a C₂-C₃ alkene, and aC₂-C₃ alkyne, and m and n may each be 1, 2 or 3.

The epoxy compound may include an epoxy compound represented by thefollowing Formula 2, and the curing agent may include diaminodiphenylsulfone.

A content ratio of the alumina and the aluminum nitride may be in arange of 1:0.25 to 2.

The inorganic filler may further include boron nitride.

A content ratio of the alumina, the aluminum nitride and the boronnitride may be in a range of 1:0.3 to 3:0.3 to 1.

The epoxy compound of Formula 2, the curing agent, and the inorganicfiller may be included at contents of 3 to 40% by weight, 0.5 to 30% byweight, and 30 to 96.5% by weight, respectively, based on the totalweight of the epoxy resin composition.

The epoxy resin composition may further include an amorphous epoxycompound.

According to another aspect of the present invention, there is provideda printed circuit board which includes a metal plate, an insulatinglayer formed on the metal plate, and a circuit pattern formed on theinsulating layer, wherein the insulating layer is made of the epoxyresin composition according to one exemplary embodiment of the presentinvention.

Advantageous Effects

According to exemplary embodiments of the present invention, an epoxyresin composition can be obtained. When the epoxy resin composition isused, an insulating layer having high thermal conductivity can beobtained, and reliability and heat dissipation performance of theprinted circuit board can be improved.

DESCRIPTION OF DRAWINGS

FIG. 1 is a cross-sectional view of a printed circuit board according toone exemplary embodiment of the present invention.

BEST MODE

The present invention may be modified in various forms and have variousembodiments, and thus particular embodiments thereof will be illustratedin the accompanying drawings and described in the detailed description.However, it should be understood that the description set forth hereinis not intended to limit the present invention, and encompasses allmodifications, equivalents, and substitutions that do not depart fromthe spirit and scope of the present invention.

Although the terms encompassing ordinal numbers such as first, second,etc. may be used to describe various elements, these elements are notlimited by these terms. These terms are only used for the purpose ofdistinguishing one element from another. For example, a first elementcould be termed a second element, and, similarly, a second element couldbe termed a first element without departing from the scope of thepresent invention. The term “and/or” includes any and all combinationsof a plurality of associated listed items.

The terminology provided herein is merely used for the purpose ofdescribing particular embodiments, and is not intended to be limiting ofexemplary embodiments of the present invention. The singular forms “a,”“an” and “the” are intended to include the plural forms as well, unlessthe context clearly indicates otherwise. It should be understood thatthe terms “comprises,” “comprising,” “includes” and/or “including,” whenused herein, specify the presence of stated features, integers, steps,operations, elements, components and/or combinations thereof, but do notpreclude the presence or addition of one or more other features,integers, steps, operations, elements, components and/or combinationsthereof.

Unless defined otherwise, all the terms (including technical andscientific terms) used herein have the same meaning as commonlyunderstood by one of ordinary skill in the art to which the presentinvention belongs. It will be further understood that the terms, such asthose defined in commonly used dictionaries, should be interpreted ashaving meanings that are consistent with their meanings in the contextof the relevant art, and will not be interpreted in an idealized oroverly formal sense unless expressly defined otherwise herein.

It will be understood that when it is assumed that a part such as alayer, film, region, or board is disposed “on” another part, it can bedirectly disposed on the other part or intervening parts may also bepresent therebetween. On the other hand, it will be understood that whenit is assumed that a part such as a layer, film, region, or board is“directly disposed on” another part, no intervening parts may be presenttherebetween.

Hereinafter, exemplary embodiments of the present invention will bedescribed in detail with reference to the accompanying drawings.Regardless of reference numerals, like numbers refer to like elementsthroughout the description of the figures, and the description of thesame elements will be not reiterated.

In this specification, the term “% by weight(s)” may be replaced with“part(s) by weight.”

To obtain an insulating layer having high heat resistance and thermalconductivity and a printed circuit board including the insulating layer,an epoxy resin composition including an epoxy resin having a mesogenicstructure, a curing agent, and an inorganic filler may be used. In thiscase, the heat resistance and thermal conductivity may vary dramaticallyaccording to the type and mixing ratio of the inorganic filler.

According to an aspect of the present invention, there is provided anepoxy resin composition which includes an epoxy resin having a mesogenicstructure, a curing agent, and an inorganic filler, wherein alumina(Al₂O₃) and aluminum nitride (AlN) are used together as the inorganicfiller. Here, mesogen is a fundamental unit of a liquid crystal, andincludes a rigid structure. For example, the mesogen may include a rigidstructure like biphenyl, phenyl benzoate, naphthalene, etc.

The epoxy resin composition according to one exemplary embodiment of thepresent invention may include the epoxy compound at a content of 3% byweight to 40% by weight, preferably 5% by weight to 20% by weight, andmore preferably 7% by weight to 15% by weight, based on the total weightof the epoxy resin composition. When the epoxy compound is included at acontent of 3% by weight or less based on the total weight of the epoxyresin composition, an adhesive property may be degraded. When the epoxycompound is included at a content of 40% by weight or more based on thetotal weight of the epoxy resin composition, it may be difficult toadjust the thickness. In this case, the epoxy resin composition mayinclude a crystalline epoxy compound at a content of 3% by weight ormore, based on the total weight of the epoxy resin composition. Thecrystalline epoxy compound may be included at a content of 50% by weightor more, based on the total weight of the epoxy compound included in theepoxy resin composition. When the crystalline epoxy compound is includedat a content of less than 50% by weight based on the total weight of theepoxy compound, thermal conductivity may be deteriorated due to lowcrystallinity.

Here, the crystalline epoxy compound may be a mesogenic compoundrepresented by the following Formula 1.

In Formula 1, R¹ to R¹⁴ may each independently be selected from thegroup consisting of H, Cl, Br, F, a C₁-C₃ alkyl, a C₂-C₃ alkene, and aC₂-C₃ alkyne, and m and n may each be 1, 2 or 3.

The crystalline epoxy compound may also be represented by the followingFormula 2.

The epoxy equivalent weight of the epoxy compound (hereinafter referredto as 4,4′-biphenolether diglycidyl ether) of Formula 2 may be in arange of 120 to 300, preferably 150 to 200. For the physical propertiesof the epoxy compound of Formula 2, the epoxy compound had a meltingpoint of 158° C., and the ¹H NMR (CDCL₃-d6, ppm) results are as below:δ=8.58 (s, 2H), δ=8.17-8.19 (d, 4H), δ=7.99-8.01 (d, 4H), δ=7.33 (s,4H), δ=4.69-4.72 (d, 1H), δ=4.18-4.22 (m, 1H), δ=3.36-3.40 (m, 1H),δ=2.92-2.94 (m, 1H) and δ=2.74-2.77 (m, 1H). The melting point wasmeasured at a heating rate of 10° C./min using a differential scanningcalorimetry device (DSC Q100 commercially available from TA InstrumentsLtd.). The NMR measurement was performed using H-NMR after the epoxycompound is dissolved in CDCL₃-d6.

The epoxy compound of Formula 2 is crystalline at room temperature. Theexpression of crystallinity may be confirmed using the endothermic peaksof crystals in differential scanning calorimetric analysis. In thiscase, the endothermic peak may be shown as a plurality of peaks or broadpeaks, the lowest temperature of the endothermic peak may be greaterthan or equal to 60° C., preferably 70° C., and the highest temperatureof the endothermic peak may be less than or equal to 120° C., preferably100° C.

Meanwhile, the epoxy compound of Formula 2 has high thermal conductioncharacteristics due to its high crystallinity, but may show insufficientroom-temperature stability. To improve such problems, the epoxy resincomposition may further include another typical amorphous epoxy compoundcontaining two or more epoxy groups in the molecule in addition to thecrystalline epoxy compound of Formula 1 or 2. The amorphous epoxycompound may be included at a content of 5% by weight to 50% by weight,preferably 10% by weight to 40% by weight, based on the total weight ofthe epoxy compound. When the amorphous epoxy compound is included at acontent of less than 5% by weight based on the total weight of the epoxycompound, the room-temperature stability may not be sufficient. On theother hand, when the amorphous epoxy compound is included at a contentof greater than 50% by weight, the thermal conduction characteristicsmay not be sufficient.

The amorphous epoxy compound may, for example, include at least oneselected from the group consisting of bisphenol A, bisphenol F,3,3′,5,5′-tetramethyl-4,4′-dihydroxydiphenyl methane,4,4′-dihydroxydiphenyl sulfone, 4,4′-dihydroxydiphenyl sulfide,4,4′-dihydroxydiphenyl ketone, fluorene bisphenol,4,4′-biphenoL-3,3′,5,5′-tetramethyl-4,4′-dihydroxybiphenyl,2,2′-biphenol, resorcinol, catechol, t-butylcatechol, hydroquinone,t-butylhydroquinone, 1,2-dihydroxynaphthalene, 1,3-dihydroxynaphthalene,1,4-dihydroxynaphthalene, 1,5-dihydroxynaphthalene,1,6-dihydroxynaphthalene, 1,7-dihydroxynaphthalene,1,8-dihydroxynaphthalene, 2,3-dihydroxynaphthalene,2,4-dihydroxynaphthalene, 2,5-dihydroxynaphthalene,2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene,2,8-dihydroxynaphthalene, an allylated or polyallylated compound of thedihydroxynaphthalene, a divalent phenol such as allylated bisphenol A,allylated bisphenol F, or allylated phenol novolac, or a trivalent ormore phenol such as phenol novolac, bisphenol A novolac, o-cresolnovolac, m-cresol novolac, p-cresol novolac, xylenol novolac,poly-p-hydroxystyrene, tris-(4-hydroxyphenyl)methane,1,1,2,2-tetrakis(4-hydroxyphenyl)ethane, phloroglucinol, pyrogallol,t-butylpyrogallol, allylated pyrogallol, polyallylated pyrogallol,1,2,4-benzenetriol, 2,3,4-trihydroxybenzophenone, a phenol aralkylresin, a naphthol aralkyl resin, or a dicyclopentadiene-based resin, aglycidyl-esterified compound derived from a halogenated bisphenol suchtetrabromobisphenol A, and a mixture thereof.

One example of the bisphenol A type epoxy compound includes a compoundrepresented by Formula 3.

In Formula 3, n is an integer greater than or equal to 1.

One example of the bisphenol F type epoxy compound includes a compoundrepresented by Formula 4.

The epoxy resin composition according to one exemplary embodiment of thepresent invention may include the curing agent at a content of 0.5% byweight to 30% by weight, preferably 3% by weight to 15% by weight, andmore preferably 5% by weight to 10% by weight, based on the total weightof the epoxy resin composition. When the curing agent is included at acontent of 0.5% by weight or less based on the total weight of the epoxyresin composition, an adhesive property may be degraded. On the otherhand, when the curing agent is included at a content of 30% by weight ormore based on the total weight of the epoxy resin composition, it may bedifficult to adjust the thickness. The curing agent included in theepoxy resin composition may be 4,4′-diaminodiphenyl sulfone representedby the following Formula 5. The curing agent of Formula 5 may react withthe epoxy compound of Formula 2 to improve thermal stability of theepoxy resin composition.

The epoxy resin composition may further include at least one selectedfrom the group consisting of a phenolic curing agent, an amine-basedcuring agent, and an acid anhydride-based curing agent.

For example, the phenolic curing agent may include at least one selectedfrom the group consisting of bisphenol A, bisphenol F,4,4′-dihydroxydiphenyl methane, 4,4′-dihydroxydiphenyl ether,1,4-bis(4-hydroxyphenoxy)benzene, 1,3-bis(4-hydroxyphenoxy)benzene,4,4′-dihydroxydiphenyl sulfide, 4,4′-dihydroxydiphenyl ketone,4,4′-dihydroxydiphenyl sulfone, 4,4′-dihydroxybiphenyl,2,2′-dihydroxybiphenyl,10-(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide,phenol novolac, bisphenol A novolac, o-cresol novolac, m-cresol novolac,p-cresol novolac, xylenol novolac, poly-p-hydroxystyrene, hydroquinone,resorcinol, catechol, t-butylcatechol, t-butylhydroquinone,phloroglucinol, pyrogallol, t-butylpyrogallol, allylated pyrogallol,polyallylated pyrogallol, 1,2,4-benzenetriol,2,3,4-trihydroxybenzophenone, 1,2-dihydroxynaphthalene,1,3-dihydroxynaphthalene, 1,4-dihydroxynaphthalene,1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene,1,7-dihydroxynaphthalene, 1,8-dihydroxynaphthalene,2,3-dihydroxynaphthalene, 2,4-dihydroxynaphthalene,2,5-dihydroxynaphthalene, 2,6-dihydroxynaphthalene,2,7-dihydroxynaphthalene, 2,8-dihydroxynaphthalene, an allylated orpolyallylated compound of the dihydroxynaphthalene, allylated bisphenolA, allylated bisphenol F, allylated phenol novolac, allylatedpyrogallol, and a mixture thereof.

For example, the amine-based curing agent may include an aliphaticamine, a polyether polyamine, an alicyclic amine, an aromatic amine,etc. The aliphatic amine may include at least one selected from thegroup consisting of ethylenediamine, 1,3-diaminopropane,1,4-diaminopropane, hexamethylenediamine,2,5-dimethylhexamethylenediamine, trimethylhexamethylenediamine,diethylenetriamine, iminobis propylamine, bis(hexamethylene)triamine,triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine,N-hydroxyethyl ethylenediamine, tetra(hydroxyethyl)ethylenediamine, etc.The polyether polyamine may include at least one selected from the groupconsisting of triethylene glycol diamine, tetraethylene glycol diamine,diethylene glycol bis(propylamine), polyoxypropylene diamine, apolyoxypropylene triamine, and a mixture thereof. The alicyclic aminemay include at least one selected from the group consisting ofisophorone diamine, methacene diamine, N-aminoethylpiperazine,bis(4-amino-3-methyldicyclohexyl)methane, bis(aminomethyl)cyclohexane,3,9-bis(3-aminopropyl)-2,4,8,10-tetraoxaspiro(5,5)undecane, norbornenediamine, etc. The aromatic amine at least one selected from the groupconsisting of tetrachloro-p-xylenediamine, m-xylenediamine,p-xylenediamine, m-phenylenediamine, o-phenylenediamine,p-phenylenediamine, 2,4-diaminoanisole, 2,4-toluenediamine,2,4-diaminodiphenylmethane, 4,4′-diaminodiphenylmethane,4,4′-diamino-1,2-diphenylethane, 2,4-diaminodiphenylsulfone,m-aminophenol, m-aminobenzylamine, benzyldimethylamine,2-dimethylaminomethyl)phenol, triethanolamine, methylbenzylamine,α-(m-aminophenyl)ethylamine, α-(p-aminophenyl)ethylamine,diaminodiethyldimethyldiphenylmethane,α,α′-bis(4-aminophenyl)-p-diisopropylbenzene, and a mixture thereof.

For example, the acid anhydride-based curing agent may include at leastone selected from the group consisting of a dodecenyl succinicanhydride, a polyadipic anhydride, a polyazelaic anhydride, apolysebacic anhydride, a poly(ethyl octadecanoic diacid) anhydride, apoly(phenyl hexadecane diacid) anhydride, a methyltetrahydrophthalicanhydride, a methylhexahydrophthalic anhydride, a hexahydrophthalicanhydride, a methyl himic anhydride, a tetrahydrophthalic anhydride, atrialkyl tetrahydrophthalic anhydride, a methylcyclohexene dicarboxylicanhydride, a methylcyclohexene tetracarboxylic anhydride, a phthalicanhydride, trimellitic anhydride, a pyromellitic anhydride, abenzophenone tetracarboxylic anhydride, ethylene glycol bistrimellitate,a chlorendic anhydride, a nadic anhydride, a methyl nadic anhydride, a5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexane-1,2-dicarboxylicanhydride, a 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene succinicdianhydride, a 1-methyl-dicarboxy-1,2,3,4-tetrahydro-1-naphthalenesuccinic dianhydride, and a mixture thereof.

The epoxy resin composition may further include a curing accelerator.

The epoxy resin composition according to one exemplary embodiment of thepresent invention may include the inorganic filler at a content of 30%by weight to 96.5% by weight, preferably 50% by weight to 95% by weight,and more preferably 70% by weight to 93% by weight, based on the totalweight of the epoxy resin composition. When the inorganic filler isincluded at a content of less than 30% by weight, high thermalconductivity, low thermal expansibility, and high-temperature thermalresistance of the epoxy resin composition may not be ensured. The highthermal conductivity, low thermal expansibility and high-temperaturethermal resistance are improved as the inorganic filler is added at anincreasing amount. The high thermal conductivity, low thermalexpansibility and high-temperature thermal resistance are not improvedaccording to the volume fraction of the inorganic filler, but start tobe dramatically improved when the inorganic filler is added at a certainamount. However, when the inorganic filler is included at a content ofgreater than 96.5% by weight, formability is deteriorated due to anincrease in viscosity.

The inorganic filler of the epoxy resin composition according to oneexemplary embodiment of the present invention includes alumina (Al₂O₃)and aluminum nitride (AlN). The inorganic filler may have a particlediameter of 0.3 μm to 60 μm. When the particle diameter of the inorganicfiller is greater than 60 μm, processability may be degraded. On theother hand, when the particle diameter of the inorganic filler is lessthan 0.3 μm, dispersibility may be degraded.

The alumina may be included at a content of 0.5% by weight to 80% byweight, based on the total weight of the epoxy resin composition. Thealuminum nitride may be included at a content of 0.5% by weight to 80%by weight, based on the total weight of the epoxy resin composition. Inthis case, a content ratio of the alumina:aluminum nitride may be in arange of 1:0.25 to 2, preferably 1:0.5 to 1.8. When the content ratio ofthe alumina and aluminum nitride satisfies this range, superior thermalconductivity may be realized.

Meanwhile, the inorganic filler of the epoxy resin composition accordingto one exemplary embodiment of the present invention may further includeboron nitride (BN). The boron nitride may be include at a content of 80%by weight or less, based on the total weight of the epoxy resincomposition. In this case, a content ratio of the alumina:aluminumnitride:boron nitride may be in a range of 1:0.3 to 3:0.3 to 1.0,preferably 1:0.33 to 2.5:0.33 to 0.5. When the content ratio of thealumina, aluminum nitride and boron nitride satisfies this range,superior thermal conductivity may be realized.

Meanwhile, the epoxy resin composition according to one exemplaryembodiment of the present invention may include an additive at a contentof 0.1% by weight to 2% by weight, preferably 0.5% by weight to 1.5% byweight, based on the total weight of the epoxy resin composition. Forexample, the additive may be phenoxy. When the additive is added at acontent of less than 0.1% by weight, it is difficult to realize desiredproperties (for example, adhesivity). On the other hand, when theadditive is added at a content of greater than 2% by weight, formabilityis deteriorated due to an increase in viscosity.

A prepreg may be prepared by coating or impregnating a fiber base or aglass base with the epoxy resin composition according to one exemplaryembodiment of the present invention and semi-curing the epoxy resincomposition by heating.

The epoxy resin composition according to one exemplary embodiment of thepresent invention may be applied to printed circuit boards. FIG. 1 is across-sectional view of a printed circuit board according to oneexemplary embodiment of the present invention.

Referring to FIG. 1, the printed circuit board 100 includes a metalplate 110, an insulating layer 120, and a circuit pattern 130.

The metal plate 110 may be made of at least one selected from the groupconsisting of copper, aluminum, nickel, gold, platinum, and an alloythereof.

The insulating layer 120 made of the epoxy resin composition accordingto one exemplary embodiment of the present invention is formed on themetal plate 110.

The circuit pattern 130 is formed on the insulating layer 120.

When the epoxy resin composition according to one exemplary embodimentof the present invention is used for the insulating layer, the printedcircuit board having excellent heat dissipation performance may beobtained.

Hereinafter, the present invention will be described in further detailin conjunction with Examples and Comparative Examples.

EXAMPLE 1

A solution obtained by mixing 10% by weight of the crystalline epoxycompound of Formula 2, 7% by weight of 4,4′-diaminodiphenyl sulfone,0.5% by weight of phenoxy, 66% by weight of alumina, and 16.5% by weightof aluminum nitride was dried, and then cured at 180° C. for 90 minutesat a load of 40 kgf/cm² to obtain an epoxy resin composition of Example1.

EXAMPLE 2

A solution obtained by mixing 10% by weight of the crystalline epoxycompound of Formula 2, 7% by weight of 4,4′-diaminodiphenyl sulfone,0.5% by weight of phenoxy, 49.5% by weight of alumina, 16.5% by weightof aluminum nitride, and 16.5% by weight of boron nitride was dried, andthen cured at 180° C. for 90 minutes at a load of 40 kgf/cm² to obtainan epoxy resin composition of Example 2.

EXAMPLE 3

A solution obtained by mixing 10% by weight of the crystalline epoxycompound of Formula 2, 7% by weight of 4,4′-diaminodiphenyl sulfone,0.5% by weight of phenoxy, 33% by weight of alumina, and 49.5% by weightof aluminum nitride was dried, and then cured at 180° C. for 90 minutesat a load of 40 kgf/cm² to obtain an epoxy resin composition of Example3.

EXAMPLE 4

A solution obtained by mixing 10% by weight of the crystalline epoxycompound of Formula 2, 7% by weight of 4,4′-diaminodiphenyl sulfone,0.5% by weight of phenoxy, 20.625% by weight of alumina, 51.5625% byweight of aluminum nitride, and 10.3125% by weight of boron nitride wasdried, and then cured at 180° C. for 90 minutes at a load of 40 kgf/cm²to obtain an epoxy resin composition of Example 4.

EXAMPLE 5

A solution obtained by mixing 5% by weight of the crystalline epoxycompound of Formula 2, 5% by weight of bisphenol A, 7% by weight of4,4′-diaminodiphenyl sulfone, 0.5% by weight of phenoxy, 20.625% byweight of alumina, 51.5625% by weight of aluminum nitride, and 10.3125%by weight of boron nitride was dried, and then cured at 180° C. for 90minutes at a load of 40 kgf/cm² to obtain an epoxy resin composition ofExample 5.

COMPARATIVE EXAMPLE 1

A solution obtained by mixing 10% by weight of bisphenol A, 7% by weightof 4,4′-diaminodiphenyl sulfone, 0.5% by weight of phenoxy, and 82.5% byweight of alumina was dried, and then cured at 180° C. for 90 minutes ata load of 40 kgf/cm² to obtain an epoxy resin composition of ComparativeExample 1.

COMPARATIVE EXAMPLE 2

A solution obtained by mixing 10% by weight of the crystalline epoxycompound of Formula 2, 7% by weight of 4,4′-diaminodiphenyl sulfone,0.5% by weight of phenoxy, and 82.5% by weight of alumina was dried, andthen cured at 180° C. for 90 minutes at a load of 40 kgf/cm² to obtainan epoxy resin composition of Comparative Example 2.

COMPARATIVE EXAMPLE 3

A solution obtained by mixing 10% by weight of bisphenol A, 7% by weightof 4,4′-diaminodiphenyl sulfone, 0.5% by weight of phenoxy, 66% byweight of alumina, and 16.5% by weight of boron nitride was dried, andthen cured at 180° C. for 90 minutes at a load of 40 kgf/cm² to obtainan epoxy resin composition of Comparative Example 3.

Thermal conductivity of the epoxy resin compositions of Example 1 to 5and Comparative Example 1 to 3 was measured by means of a transienthot-wire method using a thermal conductivity meter (LFA447 commerciallyavailable from Netzsch-Gerätebau GmbH). The measured results are listedin Table 1.

TABLE 1 Experiment No. Thermal conductivity (W/m · K) Example 1 9Example 2 10 Example 3 11 Example 4 12 Example 5 10 Comparative Example1 4 Comparative Example 2 6 Comparative Example 3 7

As listed in Table 1, it could be seen that the epoxy resincompositions, which included the crystalline epoxy compound of Formula2,4,4′-diaminodiphenyl sulfone, alumina and aluminum nitride had highthermal conductivity.

That is, the epoxy resin compositions including the crystalline epoxycompound of Formula 2, 4,4′-diaminodiphenyl sulfone, alumina andaluminum nitride as in Examples 1 and 3 had higher thermal conductivitythan the epoxy resin composition including the crystalline epoxycompound of Formula 2, 4,4′-diaminodiphenyl sulfone and alumina as inComparative Example 2.

Also, when the content ratio of the alumina and aluminum nitride wasadjusted as in Example 3, or boron nitride was further added as theinorganic filler as in Examples 2 and 4, the superior thermalconductivity was able to be realized.

Although the preferred embodiments of the present invention have beenshown and described in detail, it would be appreciated by those skilledin the art that modifications and changes may be made in theseembodiments without departing from the scope of the invention, the scopeof which is defined in the claims and their equivalents.

The invention claimed is:
 1. An epoxy resin composition comprising: anepoxy compound represented by the following Formula 1; a curing agentcomprising diaminodiphenyl sulfone; and an inorganic filler, wherein theinorganic filler comprises alumina (Al₂O₃), aluminum nitride (AlN), andboron nitride (BN):

wherein each of R¹ to R¹⁴ is independently selected from the groupconsisting of H, Cl, Br, F, a C₁-C₃ alkyl, a C₂-C₃ alkene, and a C₂-C₃alkyne, and each of m and n is 1, 2 or 3, wherein a weight ratio of thealumina, the aluminum nitride, and the boron nitride is in a range of1:0.33 to 2.5:0.33 to 0.5.
 2. The epoxy resin composition of claim 1,wherein the epoxy compound comprises an epoxy compound represented bythe following Formula 2:


3. The epoxy resin composition of claim 1, wherein each of m and n is 2or
 3. 4. The epoxy resin composition of claim 3, wherein each of m and nis
 3. 5. The epoxy resin composition of claim 1, wherein the epoxycompound of Formula 1, the curing agent, and the inorganic filler areincluded at contents of 3 to 40% by weight, 0.5 to 30% by weight, and 30to 96.5% by weight, respectively, based on the total weight of the epoxyresin composition.
 6. The epoxy resin composition of claim 1, furthercomprising an amorphous epoxy compound.
 7. The epoxy resin compositionof claim 1, further comprising phenoxy.
 8. A printed circuit boardcomprising: a metal plate, an insulating layer formed on the metalplate; and a circuit pattern formed on the insulating layer, wherein theinsulating layer is made of the epoxy resin composition defined inclaim
 1. 9. The printed circuit board of claim 8, wherein each of m andn is 2 or
 3. 10. The printed circuit board of claim 9, wherein each of mand n is 3.